Out prior U.S. Pat. No. 5,505,728, whose contents are hereby incorporated by reference, describes a novel electrode and electrosurgical procedure for treating Obstructive Sleep Apnea Syndrome (OSAS) by shaving off superficial thin layers of patient airway obstructing tissue.
Our referenced U.S. application, Ser. No. 09/303,839, whose contents are hereby incorporated by reference, describes apparatus for use in a surgical procedure commonly known as minimally invasive surgery (MIS), for treating, say, a herniated disk to remove undesired regions and to provide controlled heat to shrink the tissue during surgery. The electrode for MIS use is preferably constructed with a flexible end controllable by the surgeon so as to allow the surgeon to manipulate the end as desired during the surgical procedure.
This tissue shrinking concept has recently been extended to the treatment of other disorders. It is known as Radio Frequency Thermal Ablation (RFTA), which uses radio frequency (RF) heating to create targeted tissue ablation resulting in tissue volume reduction. One proposed application, described in a paper published in Kania, Sep. 25, 1999 by Pr. B. Meyer, is for the treatment of OSAS and more generally sleep disordered breathing (SDB). The proposed procedure is to insert an electrode into the tongue base below the uvula and apply RF energy such that resistive heating of the tissue occurs, raising the temperature of the immediately surrounding tissue to a temperature that damages or kills the cells. This produces a small lesion which is later replaced by scar tissue and removed by the body, resulting in the shrinkage or volumetric reduction of the treated tissue. This procedure by reducing the volume of the local tissue may enlarge the airway alleviating SDB.
The present invention describes a novel electrode that can be used with low voltage, low power electrosurgical apparatus for the purpose of implementing RFTA with a relatively simple, easily learned procedure.
Briefly stated, the novel electrode comprises a generally L-shaped metal member comprising an electrically-insulated, generally straight shank part for mounting in a standard electrosurgical handpiece, and a generally curved needle-shaped part divided into first, second, third, and fourth sections, the second, third, and fourth of which are electrically-insulating and the first of which, the active section, is bare and terminates in a pointed end. The second and third sections are covered with a thin electrically-insulating coating, whereas the fourth section, closest to the shank, is covered with a thicker electrically-insulating coating. The first, second, and third sections are dimensioned and constructed so as to enable the surgeon to know fairly precisely the depth of the active first section in the targeted tissue. In a preferred embodiment, each of the first, second, and third sections are about 1 cm long, and the electrically-insulating coatings on the second and third sections are color-coded differently so they can be visually distinguished so as to enable the surgeon to determine the depth in the tissue of the active first section by the color of the needle-shaped electrode part remaining outside of the tissue.
For completeness"" sake, attention is directed to our U.S. Pat. No. 5,755,716, which describes an electrode for treating glaucoma, but this electrode is unsuitable for treating SDB because the electrode has no point capable of penetrating tough tongue base tissue, and one side of the active end is coated, which means that the heat generated is assymetrical about the electrode and will not achieve the results desired. Attention is also directed to our U.S. Pat. No. 5,571,101, which describes an electrode for a DCR procedure, but this electrode is unsuitable for treating SDB because the electrode tip is too short, and does not have 2 separate thin-coated sections following the bare section. Moreover, both patents describe the use of their electrode with conventional high-voltage electrosurgical apparatus for excising or cutting tissue by using current discharges rather than the low-power, low-voltage apparatus needed for RFTA which relies on resistive heating.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention.